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Proceedings Paper

Effects of geometric nonlinearities of shape memory alloy springs on the aeroelastic behavior of a typical aeroelastic section
Author(s): Vagner Candido de Sousa; Carlos De Marqui; Mohammad H. Elahinia
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Paper Abstract

The effects of the pseudoelastic hysteresis of shape memory alloy (SMA) springs with different geometries on the aeroelastic behavior of a two-degree-of-freedom typical section are investigated in this work. The ratio of the spring coil diameter to the wire diameter (spring index) is changed, yielding diversified levels of nonlinearity of the mechanical response of the SMA springs and, consequently, changing the aeroelastic behavior of the typical section. A classical phenomenological model for SMAs under uniaxial loading is modified with the pure shear assumption to model SMA helical springs. The aeroelastic model of the typical section with SMAs is cast into state-space representation along with a two-state unsteady aerodynamic model. The resulting equations are solved over time with a Runge-Kutta scheme. The axial deflections of the SMA springs are determined based on the pitch displacement of the typical section, which allow the determination of the shear strain at the perimeter of the coiled SMA wire. The corresponding nonlinear shear stress and martensitic fraction are determined iteratively. It is shown that the hysteretic damping may decrease the amplitudes of oscillation of the airfoil at the flutter boundary. Overall, the aeroelastic behavior of the typical section with SMAs undergoing phase transformation is sensitive to the geometric characteristics of the SMA springs and specific configurations lead to enhanced operation.

Paper Details

Date Published:
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Proc. SPIE 9803, Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2016, 98032B; doi: 10.1117/12.2219283
Show Author Affiliations
Vagner Candido de Sousa, Univ. de São Paulo (Brazil)
Carlos De Marqui, Univ. de São Paulo (Brazil)
Mohammad H. Elahinia, The Univ. of Toledo (United States)


Published in SPIE Proceedings Vol. 9803:
Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2016
Jerome P. Lynch, Editor(s)

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